<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        margin: 0;
        padding: 0;
    }
    .w{
        margin: 100px auto;
    }
    .hezi{
        width: 800px;
        height: 50px;
        
    }
    input{
        float: right;
        width: 230px;
        height: 50px;
        outline: none;
        padding-left: 10px;
        border: 2px solid red;
        border-right: 0;
        transition: all 1s;
        /* animation: name duration timing-function delay iteration-count direction fill-mode; */
    
    }
    .hezi:hover input{
        /* animation: move 1s  alternate forwards; */
        width: 600px;
    }
    /* button:hover{
        width: 80px;
    } */
    button{
        float: right;
        width: 69px;
        height: 54px;
        border: none;
        background-color: red;
        color: #fff;
        /* transition: all 1s; */
        font-size: 14px;
    }
    /* @keyframes move{
        0%{
            
        }
        100%{
            width: 600px;
        }
    } */
</style>
<body>
    <div class="hezi w">
        <button>搜索</button>
    <input type="text" placeholder="有点东西哦">
    
</div>
</body>
</html>